Non-linear junction detectors (NLJD) are used to detect harmonic signals re-radiated from a non-linear junction in response to a transmitted signal. Non-linear junctions are typically found in two main categories of things, corrosive metal junctions and semiconductor containing electronics. NLJDs can detect these junctions whether they are concealed or operating.
A NLJD is used in a fashion similar to a hand-held metal detector and a highly technically skilled operator is not required to use the device. As a result, there are large number of practical everyday applications for NLJDs. For example, NLJDs are used to detect lost or concealed electronics in items such as mud, tall grass or concrete, or inside of a wall, pipe or furniture, without the need to tear up the item being searched and regardless of whether the devices are operating. NLJDs are also used to detect corrosion or defects in pipes or welds and to trace certain types of buried or hidden cables and wires. NLJDs are used by security forces to search for mobile phones and weapons.
NLJDs are also one of the main tools used in performing counter surveillance sweeps, or Technical Surveillance Counter Measures (TSCM). TSCM are the security processes of ensuring that a room or area within a building does not contain any illegal or nefarious bugging devices such as microphones, hidden surveillance cameras, digital recorders, or radio frequency (RF) transmitters. There are a wide range of organizations that benefit from sweep services including commercial, law enforcement, and government organizations. While government organizations are often concerned with political or military information; commercial organizations have a great need for sweep operations to protect information such as trade secrets, new product developments or technology, marketing plans, mergers and acquisitions, important employee information, etc. Furthermore, TSCM operations play a big role in VIP protection plans for political figures, sports figures, celebrities, etc. A NLJD is a very useful tool for performing sweeps because it provides the ability to detect the presence of hidden surveillance devices, even when the device's electronics are not operating, or turned on, or concealed in concrete.
Thus, there is an existing need for NLJDs and improvements to their design and functionality that allow them to better perform their numerous commercial and governmental tasks.